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/ Fragment實例精講——新聞(購物)類App列表Fragment的簡單實現(xiàn)
Fragment實例精講——新聞(購物)類App列表Fragment的簡單實現(xiàn)
本節(jié)引言：
相信大家對點擊列表，然后進入詳情這種App并不陌生吧，在購物類App和新聞類App中最為常見： 下面我們簡單來講一下流程邏輯！
邏輯流程講解：
剛好公司測試妹子的測試機上裝了楚楚街9塊9的APP，呵呵，直接就照這個來研究吧：
嘿嘿，市面上很多APP都是這種樣子的，而這個可以用我們學(xué)到的Fragment來實現(xiàn)： 可能gif動畫看不清，筆者用界面原型工具畫個大概吧：
大概就這樣，中間區(qū)域是一個布局容器，一般是FrameLayout，然后我們將一個Fragment replace 到這個容器中或者add也行，而這個Fragment中有一個listview，當我們點擊這個ListView中的一項， 中間容器中的Fragment就會被replace成對應(yīng)詳細信息的Fragment所替代，如果我們只是replace的話， 就不會保存第一個Fragment的狀態(tài)，用戶又得從頭開始瀏覽，這肯定是很不方便的，這里我們可以 通過Fragment棧的addtobackStack和popbackstack來解決這個問題！當replace的同時，我們將被替換 的Fragment添加到stack中，當用戶點擊回退按鈕時，調(diào)用popbackstack彈出棧，具體實現(xiàn)見下述代碼 示例！
2.代碼示例：簡單新聞類APP列表和內(nèi)容切換的實現(xiàn)
運行效果圖：
實現(xiàn)代碼：
Step 1:先把兩個Fragment以及Activity的布局實現(xiàn)了
fg_newlist.xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="../style/images/white" android:orientation="horizontal"> <ListView android:id="@+id/list_news" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout>
fg_context.xml:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <TextView android:id="@+id/txt_content" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:textColor="../style/images/blue" android:textSize="20sp" /> </LinearLayout>
activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:id="@+id/txt_title" android:layout_width="match_parent" android:layout_height="56dp" android:background="../style/images/blue" android:textColor="../style/images/white" android:text="新聞列表" android:textSize="20sp" android:textStyle="bold" android:gravity="center"/> <FrameLayout android:id="@+id/fl_content" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/txt_title"/> </RelativeLayout>
Step 2:實現(xiàn)我們的業(yè)務(wù)Bean類和自定義BaseAdapter類：
Data.java:
/**
* Created by Jay on 2015/9/6 0006.
*/
public class Data {
private String new_title;
private String new_content;
public Data(){}
public Data(String new_title, String new_content) {
this.new_title = new_title;
this.new_content = new_content;
}
public String getNew_title() {
return new_title;
}
public String getNew_content() {
return new_content;
}
public void setNew_title(String new_title) {
this.new_title = new_title;
}
public void setNew_content(String new_content) {
this.new_content = new_content;
}
}MyAdapter.java:
/**
* Created by Jay on 2015/9/6 0006.
*/
public class MyAdapter extends BaseAdapter{
private List<Data> mData;
private Context mContext;
public MyAdapter(List<Data> mData, Context mContext) {
this.mData = mData;
this.mContext = mContext;
}
@Override
public int getCount() {
return mData.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if(convertView == null){
convertView = LayoutInflater.from(mContext).inflate(R.layout.list_item,parent,false);
viewHolder = new ViewHolder();
viewHolder.txt_item_title = (TextView) convertView.findViewById(R.id.txt_item_title);
convertView.setTag(viewHolder);
}else{
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.txt_item_title.setText(mData.get(position).getNew_title());
return convertView;
}
private class ViewHolder{
TextView txt_item_title;
}
}Step 3:MainActivity的實現(xiàn)
MainActivity.java:
public class MainActivity extends AppCompatActivity {
private TextView txt_title;
private FrameLayout fl_content;
private Context mContext;
private ArrayList<Data> datas = null;
private FragmentManager fManager = null;
private long exitTime = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = MainActivity.this;
fManager = getFragmentManager();
bindViews();
datas = new ArrayList<Data>();
for (int i = 1; i <= 20; i++) {
Data data = new Data("新聞標題" + i, i + "~新聞內(nèi)容~~~~~~~~");
datas.add(data);
}
NewListFragment nlFragment = new NewListFragment(fManager, datas);
FragmentTransaction ft = fManager.beginTransaction();
ft.replace(R.id.fl_content, nlFragment);
ft.commit();
}
private void bindViews() {
txt_title = (TextView) findViewById(R.id.txt_title);
fl_content = (FrameLayout) findViewById(R.id.fl_content);
}
//點擊回退鍵的處理：判斷Fragment棧中是否有Fragment
//沒，雙擊退出程序，否則像是Toast提示
//有，popbackstack彈出棧
@Override
public void onBackPressed() {
if (fManager.getBackStackEntryCount() == 0) {
if ((System.currentTimeMillis() - exitTime) > 2000) {
Toast.makeText(getApplicationContext(), "再按一次退出程序",
Toast.LENGTH_SHORT).show();
exitTime = System.currentTimeMillis();
} else {
super.onBackPressed();
}
} else {
fManager.popBackStack();
txt_title.setText("新聞列表");
}
}
}Step 4:列表Fragment的實現(xiàn)：
NewListFragment.java：
package com.jay.fragmentdemo4;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
/**
* Created by Jay on 2015/9/6 0006.
*/
public class NewListFragment extends Fragment implements AdapterView.OnItemClickListener {
private FragmentManager fManager;
private ArrayList<Data> datas;
private ListView list_news;
public NewListFragment(FragmentManager fManager, ArrayList<Data> datas) {
this.fManager = fManager;
this.datas = datas;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fg_newlist, container, false);
list_news = (ListView) view.findViewById(R.id.list_news);
MyAdapter myAdapter = new MyAdapter(datas, getActivity());
list_news.setAdapter(myAdapter);
list_news.setOnItemClickListener(this);
return view;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
FragmentTransaction fTransaction = fManager.beginTransaction();
NewContentFragment ncFragment = new NewContentFragment();
Bundle bd = new Bundle();
bd.putString("content", datas.get(position).getNew_content());
ncFragment.setArguments(bd);
//獲取Activity的控件
TextView txt_title = (TextView) getActivity().findViewById(R.id.txt_title);
txt_title.setText(datas.get(position).getNew_content());
//加上Fragment替換動畫
fTransaction.setCustomAnimations(R.anim.fragment_slide_left_enter, R.anim.fragment_slide_left_exit);
fTransaction.replace(R.id.fl_content, ncFragment);
//調(diào)用addToBackStack將Fragment添加到棧中
fTransaction.addToBackStack(null);
fTransaction.commit();
}
}Step 5:內(nèi)容Fragment的實現(xiàn)：
NewContentFragment.java:
/**
* Created by Jay on 2015/9/6 0006.
*/
public class NewContentFragment extends Fragment {
NewContentFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fg_content, container, false);
TextView txt_content = (TextView) view.findViewById(R.id.txt_content);
//getArgument獲取傳遞過來的Bundle對象
txt_content.setText(getArguments().getString("content"));
return view;
}
}代碼很簡單，就不慢慢解釋了~
3.代碼下載
FragmentDemo5.zip：下載 FragmentDemo5.zip
本節(jié)小結(jié)：
因為時間的關(guān)系，并沒有詳細的去做過多的講解，示例代碼也很簡單，方便各位初學(xué)者理解！ 如果要用到實際項目中還需要對此進行一番修改~！好的，本節(jié)就到這里，謝謝~